The use of sophisticated sensors and navigation techniques in Deep Trekker remotely operated vehicles (ROVs) supports a variety of industries, including marine research, search and recovery, underwater inspections, aquaculture, offshore infrastructure maintenance, and environmental monitoring, among others.
Equipped with dependable positioning and navigation systems for complex underwater settings, Deep Trekker ROVs enable engineers, scientists, and business operators to perform underwater tasks with precision, reliability, and efficiency.
Deep Trekker integrates an array of advanced sensors and methodologies to address the complexities of underwater navigation, facilitating accurate underwater positioning.
To improve underwater navigation, Deep Trekker has conducted thorough assessments of various positioning systems, analyzing operational challenges and real-world performance. Nemanja Kliska, Deep Trekker’s Team Lead and Autonomy Systems Engineer, provides detailed insights into the distinctions, functionalities, and trade-offs of these systems.
Deep Trekker has crafted an optimized solution by combining DVL with IMU technology, achieving an effective balance between cost and performance. This approach rivals industry leaders but at a significantly lower cost, broadening access to advanced positioning technologies.
Comparing the Deep Trekker System to FOG IMUs
One major difference between FOG IMUs and the more cost-effective MEMS lies in their susceptibility to magnetic interference. Kliska noted, “While both MEMS and FOG IMUs offer accurate Dead Reckoning, FOG IMUs do not utilize a compass and therefore excel in environments with significant magnetic interference, such as near metal wrecks or ships. Their stability remains unaffected, ensuring precise navigation even in challenging conditions.”
Another notable distinction involves pre-mission preparation. FOG IMUs require initialization on land, needing 10-15 minutes of stillness on a stable surface. This process cannot be performed onboard a vessel, necessitating careful pre-mission planning.
This contrasts with the more flexible deployment options offered by systems like Deep Trekker’s Dead Reckoning implementation with observation class ROVs.
Addressing Underwater Navigation Challenges
Deep Trekker’s navigation systems are designed to adapt to diverse underwater conditions. For ship hull inspections, where magnetic interference is common, MEMS IMUs offer flexibility and rapid deployment, making them suitable for dynamic applications. The company has developed real-time mode-switching capabilities in its ROVs to handle interference effectively.
Kliska added, “It’s also important to note that we have found that most of the magnetic interference happens near the engine room of the ship, allowing us to cover inspections of 95% of the submerged portions of the vessels virtually unaffected.” For the remaining areas, switching modes allows uninterrupted inspections in ferrous environments.
This adaptability enables Deep Trekker systems to navigate obstacles and complex structures effectively, ensuring reliable performance in maritime environments impacted by magnetic interference.
IMU Testing Methodologies & Performance Evaluation
Deep Trekker utilizes robust testing methods to evaluate IMU performance in different settings. Kliska describes two approaches: top-down validation and bottom-up analysis.
Top-down validation involves ROVs navigating predefined courses to simulate real-world operations, providing practical insights into IMU performance. Meanwhile, bottom-up analysis focuses on sensor specifications and dynamic performance to refine Sensor Fusion algorithms.
This dual-layered approach allows Deep Trekker to optimize system accuracy and reliability, ensuring seamless integration of sensor data across varying conditions.
Reliability Through Real-World Validation & Customer Input
Kliska emphasized the importance of real-world validation, stating, “In addition to in-house testing, we engage with customers to address specific challenges encountered in diverse environments. For instance, mitigating issues like depth-dependent error propagation in deep-sea operations requires tailored solutions and continuous refinement.”
Feedback from field operations helps identify areas for improvement and drives innovation. By incorporating customer insights, Deep Trekker develops tailored solutions that enhance reliability and functionality in demanding underwater conditions.
Advancements in Sensor Fusion Algorithms
Deep Trekker prioritizes algorithm stability and sensor redundancy to ensure reliable navigation. Kliska explained, “Our Sensor Fusion algorithms are designed to integrate data from a variety of sensors.”
This integration process is dynamic, with the algorithms constantly recalibrating in real-time to ensure that the data remains stable and reliable, even as the conditions around the ROV change. This constant recalibration helps to smooth out any discrepancies or anomalies that might arise from individual sensor readings, leading to a more consistent and accurate navigational output.
These algorithms also include recovery mechanisms to maintain functionality in case of sensor failures. By automatically switching to backup sensors, the system ensures uninterrupted operation, offering a critical advantage for time-sensitive underwater missions.
Mitigating Magnetic Distortions & Optimizing Startup Time
Deep Trekker addresses magnetic distortions through Sensor Fusion algorithms designed to compensate for heading inaccuracies. Kliska recalled a ship hull inspection in Hamilton, Ontario, where manual adjustments were needed to account for magnetic deviations. These calibrations underscore the complexity of managing magnetic disturbances.
Simplified startup procedures further enhance usability. Unlike FOG IMUs, which require lengthy calibration on static surfaces, Deep Trekker’s systems leverage pre-calibrated sensors, allowing rapid deployment without compromising performance.
Kliska stated, “Typically, a FOG IMU requires about 15 minutes of settling time and that’s used to determine the sensor bias. With the Deep Trekker system, you can deploy right away, and you can do that off a boat, too; you don’t need to have it on the ground.”
Enhancing Dead Reckoning with USBL & GPS Augmentation
Deep Trekker highlights the integration of absolute positioning technologies, specifically USBL and GPS systems, to improve Dead Reckoning methodologies. USBL technology provides high-precision positioning in open water but faces limitations from acoustic reflections and environmental noise. These constraints demand careful setup to optimize accuracy in challenging underwater conditions.
On the other hand, GPS systems excel in delivering global positioning accuracy on the surface but cannot operate underwater, requiring seamless transitions to Dead Reckoning techniques once submerged.
Deep Trekker’s approach combines MEMS IMU and DVL configurations with USBL and ROV GPS systems, creating a versatile and reliable positioning suite tailored to meet a range of operational challenges.
